Rock drilling bit



April 19, 1932. A POWELL ROCK DRILLING Br]? Filed June 6, 1928 PatentedA r. 19,1932

UNITED STATES PATENT OFFICE ALFRED E. rowELL, or LONG BEACH, CALIFORNIA,ASSIGNOR or ONE-HALF 'ro HALL n. HOLDAWAY, or LONG BEACH, CALIFORNIA;HELEN N. HOLDAWAY ADMINIS- TRATRIX or SAID HOLDAWAY, DECEASED ROCKDRILLING BIT Application filed June 6,

This invention relates to a rock drilling bit and refers particularly toa rock drilling bit for use in drilling wells by the hydraulic rotarymethod.

An object of the present invention is to rovide a drilling bit of theclass intended or drilling through hard or semi-hard rock,

by means of roller cutters in which there is torque is transferreddirectly from the drill pipe to the cutters rather than being imposedupon the pins or bushings employed for rotatably mounting the cutters.

' bit.

A further object of the present invention is to provide a drilling bitin which the rotation of the roller cutters atthe bottom of the well, aswell as the planetating movement of the cutters is reduced for the samerotation of the drill pipe over that which is usual in bits of thistype.

0 Various further objects and advantages of the present invention willbe apparent from a description of the preferred form or example of adrilling bit employing the invention. For this purpose, reference ismade to the accompanying drawings in which there is illustrated thepreferred form of drilling In the drawings:

Figure 1 is' an elevation partially in vertical section of the drillingbit.

Figure 2 is a fragmentary elevation at right angles to Figure 1 andFigure 3 is a section on the line 33 of I Figure 1, the ends of the headand pins being removed.

Referring to the drawings, the drilling bit is illustrated as comprisinga plurality of rolling cutters 2 rotatably mounted by a head 3, whichhead in turn is rotatably mounted upon a driving member 4. The drivemefn- 1928. Serial No.283,219;

fluid will be discharged between the adjacent faces of the rollingcutters.

The driving member 4 is indicated as having an enlargement 7 at itslower end which serves as a means for holding the head 3 of the bit tothe driving member. The driving member is further shown as provided witha plurality of depending pins 8 which may be integral with the head 7,which depending pins 8 serve as means for forming a gear connectionbetween the head 7 of the driving member 4 and the roller cutters 2. Thehead 7 of the driving member 4 is also preferably provided with a recess9 at its lower end, to provide clearance between it and the outercutting edges of the cutting rollers 2. The pins 8 of the driving'memberare also indicated at 10 as cut away to clear the back surface of thecutting rollers'2.

The cutting rollers of the drilling bit are preferably made with conicalor frusto-conical cutting faces 11 which may be cut in any preferred ordesired manner into teeth or suitable cutting ridges or projections, andthe cutting rollers 2 are disposed on axes which converge substantiallyat the axis of the drilling bit. The axes of the cutting rollers 2 arepreferably at about 45 with the horizontal plane and the preferred formof the bitineludes two diametrically opposite cutting rollers. Thecutting rollers 2 are further provided at their rear ends with recesses12 for receiving pins 13 and bushings 14 which serve as a means forrotatably mounting the cutters 2 upon the head 3. The rear faces of thecutting rollers 2 are indicated as proil'ded with a tapered surface15.0f general frustro-conical shape, the apex of which is in theopposite direction to that.of the apex of the cutting face of thecutters. The base of the rear frusto-conical portion of the cutter 2 isprovided with gear teeth 16, shaped to coact with the gear pins 8 on thedriving member 4 and shaped so that in operating position, the tops ofsaid gear teeth provide bearing faces engaging the bottom of the head 7of the drive member 4, while the bottoms of the rooves formed by theteeth form additional earing surfaces engaging the bottoms of the gearpins 8. The taper of the rear face of the cutters 2 and of the top facesof the gear teeth 16 are preferably such that these bearing faces aresubstantially horizontal when they are rotated to the upper position.

The relationship between the taper of the crushing surfaces of thecutters and the taper of the driving or thrust surfaces of the cuttersmay also be described by the specification that the generating line ofthe frusto-conical crushing surface of the cone is parallel to thegenerating line of the thrust or driving surface of the cone which is onthe opposite side of the axis in any section taken through the axis ofthe cutter. Thus in Figure 1 the generating line of the driving orthrust surface of the cone which corresponds to the section line 33 isparallel to the generating line AA of the crushing surface of the conewhich is on the opposite side of the cutter axis.

The drive member 4 and its gear pins 8, and the cutting rollers 2,preferably, are so proportioned relative to each other, that thetransfer of pressure from the drive member 4 through the bearing facesdescribed, to the roller 2 take place at points vertically aligned withsubstantially the midpoint of the cutting faces of the cutters 2 at thebottom of the cutters. By this arrangement of the parts, it will be seenthat the drilling pressure is transferred directly from the drive member4 over the center of the cutting operations without the drillingpressure passing through the pins 13 and bushings 14 rotatably mountingthe cutters.

The head 3 of the drilling bit has a neck 17 having a running fit withthe driving member 4 above the head 7 of said drive member and the head3 has its bore enlarged as indicated at 18, to form a running fit withthe head 7 of the drive member. The enlargement 18 of the bore of thehead 3 is made of sufficient length, as to clear slightly the top of theenlargement 7 of the drive member. Head 3 forms two lugs 19 and 20,having upwardly tapering inner faces against which the rolling cutters 2bear and the lugs 19 and 20 have openings 21 and 22 receiving the pins13which mount the cutters 2. There is also preferably provided lock pins23 and 24 for locking the bearing pins 13 to the head 3.

In operation of the bit herein described, the drive member 4 iscontinuously rotated under. a downward pressure from 4 the drill pipewhile a flushing fluid is continuously circulated through the passage 6.The gear connection between the drive member 4 and the roller cutters 2synchronizes the rotation of the cutters and causes the roller cutters 2to planetate in the bottom of the well hole rolling upon the formation,so that the cutting teeth, ridges or projections thereof, penetrate therock formation. In the drilling operations, due to the direct impositionof both the turning torque and vertical load upon the cutters 2, thebushings 14 and bearing pins 13 of the cutters are relieved from anymaterial stresses so that the wear takes place almost exclusively uponthe cutting faces and projections of the cutters. In operation, this isfound to prevent the cutters from wearing the pins so that the cutterswill be moved into interlocking position and also further to prevent anytwisting or bending of the supporting pins and further, to prevent thecutters from being moved inwardly and changing the diameter of the wellbore. It is further found in operation, that a less torque is placed onthe drill pipe with the bit of the present invention than is customaryin previous forms of bits. decreasing the hazards of twisting the bitoff in the well hole.

Another important advantage of the present invention resides in the factthat due to the direct imposition of torque and vertical load on thecutters, a greater vertical load may be applied to it in operation thanis customary.

A bit of the present invention is found to drill more rapidly in a wellhole because of the fact that greater vertical pressure may be placed onthe bit and a slower speed of rotation of the cutters employed, whichresults in a more rapid rate of drilling with less wear of the drillingcutters.

While the form of drilling bit herein described is well adapted forcarrying out the objects of the present invention, it is understood thatvarious modifications and changes may be made without departing from theprinciples of the invention and the invention includes all such changesand modifications as come Within the scope of the appended claims.

I claim:

1. A drilling bit comprising: a drive member; roller cutters; a headrotatably mounted on said drive member and rotatably mounting saidroller cutters; means for driving said roller cutters with the rotationof said drive member;-and means for imposing vertical load directly fromthe drive member to each of said roller. cutters at a point verticallyaligned with the approximate center of the portions of the cutting facesof the cutters occupying the lower position.

2. A drilling bit comprising: a drive and supporting member; a pluralityof cutting rollers including cutting teeth andseparate gear teeth; ahead swiveled upon said drive member and revolvably mounting saidcutting rollers; and gear means carried by said drive member andengaging the gear teeth of said cutting rollers.

3. A drilling bit comprising: a drive member; a plurality of cuttingrollers, having cutting teeth and separate gear teeth; a head swivcledupon said drive member and revolvably mounting said cutting rollers; andgear means between said drive member and said cutting rollers, said gearmeans being arranged to serve as a means for transferring vertical loadfrom the drive member to the cutters.

4. A drilling bit comprising: a drive member; a plurality of cuttingrollers; a head swiveled upon said drive member and revolvably mountingsaid cutting rollers; and gear means between said drive member and saidcutting rollers, said cutting rollers having thrust receiving surfacesand cutting surfaces, said surface being arranged so that the uppermostportions of the thrust receiving surface are at all t mes disposeddirectly above the lowermost portions ofthe cutting surface, said gearmeans being thus arranged to serve as means for transferring verticalload to said cutting rollers as well as turning torque.

5. A drilling bit comprising: a head; cutting rollers having conicalcutting faces. the axes of which substantially converge at the axis ofthe bit, said cutting rollers being revolvably mounted by said head.said cutting rollers having rear faces angled relative to the conicalcutting faces, the rear faces of said cutting rollers forming bearingsurfaces a drive member extending through said head and engaging saidbearing surfaces for directly transferring vertical load to said cuttingrollers; and gear means between said cutting rollers and said drivemember.

6. A drilling bit comprising: a head; cutting rollers rotatably mountedby said head on axes converging substantially at the axis of the bit,the cutting rollers having frustoconical shaped cutting faces and havingrear bearing faces angled relative to the cutting faces; a drive memberon which said head is swiveled; and gear means between saiddrive memberand said cutters, said gear means operating to transfer the verticalload directly from the drive member to the cutting rollers in verticalalignment with the approximate center of the lower portions of thecutting surfaces of the rollers which occupy momentarily thecutting'positions.

7. A cutter for a drilling bit having a conical cutting face at one endend a conical hearing face on the other end, the apex of the cuttingface being towards the forward end of the cutter and the apex of thebearing face being towards the rear end of the cutter, said bearing faceincluding gear teeth.

8. A drilling bit comprising: a drive mem ber having an axial watercourse; a head swlveled on the drive member; cutting rollersrotatablymounted on said head in position to have their cutting facescleaned by fluid from said passages; and means for directly transferringvertical load and torque from the drive member to the cutting rollers.

9. A well drilling bit comprising: a plurality of cutting members; ahead upon which said members are rotatably mounted; a main rotatabledriving and supporting member upon which said head is swivelled: meansfor driving said cutting members with the rotation of said driving andsupporting member; and means for transmitting vertical load directlyfrom the main driving and supporting member to said cutters.

' 10. A rolling cutter for a well drilling bit, j

said rolling cutter having a main crushing surface with crushingprojections and an integral thrust receiving surface including gearteeth, said surfaces being arranged so that the uppermost portions ofthe thrust receiving surface will at all times be disposed directlyabove the lowermost portions of the cutting surface.

11. A rolling cutter for a well drilling bit, said rolling cutter havinga conical cutting and crushing surface at one end having gearlikecrushing projections shaped so that when said cutting surface is movedagainst a formation with a true rolling motion it will be geared to saidformation, the rolling cutter having a conical thrust receiving surfaceat the other end which surface includes gear teeth, the apex of theconical thrust receiving surface being disposed at the opposite end ofthe cutter from the apex of the cutting surface, said surfaces beingarranged so that the uppermost portions of the thrust receiving surfacewill at all times be disposed directly gbove the lower portions of thecutting surace. 12. A drilling bit comprising: a drive member; a head;cutting rollers rotatably mounted by said head on axes convergingsubstantially at the axis of the bit, said head being rotatable andaxially slidable on said drive member; bearing surfaces on said cuttingrollers, said drive member engaging said bearing surfaces for directlytransferring vertical load to said cutting rollers; and gear meansbetween said cutting rollers and said drive member.

13. A rotary well drilling bit comprising: a driving shank; a headrotatable about said driving shank; cutters rotatably mounted on saidhead and adapted to roll on the formation to be drilled; and gear meansconnecting said cutters with said driving shank operating asload'transmitting means, said cutters having frusto-conical crushingsurfaces and frusto-conical thrust surfaces on opposed ends thereof, thegenerating line of the conical crushing surface being parallel to thegenerating line of the conical thrust surface on the opposite side ofthe cutter axes.

14. A rotary well drilling bit comprising: a driving shank; a headrotatable about said driving shank; cutting rollers rotatably mounted onsaid head; means for driving said cutting rollers with the rotation ofsaid driving shank; and means for imposing vertical load from saiddriving shank directly upon said cutting rollers at a point verticallyaligned with approximately the center of the crushing surfaces of saidcutting rollers at the bottom of the .drilling bit.

15. A rotary well drilling bit comprising: a driving shank; a headrotatable about said driving shank; rolling cutters rotatably mounted onsaid head; and means for directly connecting said driving shank and saidrolling cutters operative for transmitting the load vertically anddrilling torque directly from said driving shank to said rollingcutters.

16. A rotary well drilling bit comprising: a driving shank; a headrotatable about said driving shank; rolling cutters rotatably mounted onsaid head; and gear means connecting said driving shank and said rollingcutters, said gear means being arranged to serve as vertical loadtransmitting means between said driving shank and said cutters and beingarranged to transmit vertical load to said cutters at points verticallyaligned with approximately the center of the crushing surfaces of saidcutters which occupy the cutting position.

17. A rotary well drilling bit comprising: a driving shank; a headrotatable about said driving shank; rolling cutters rotatably mounted onsaid head, said cutters having conical crushing surfaces and axes ofrotation substantially converging at the axis of the bit, said cuttershaving rear conical thrust receiving surfaces; and driving meansconnecting said driving shank with said rear thrust receiving surfacesof said cutters for directly transmitting vertical load and drillingtorque to said rolling cutters.

18. A rotary well drilling bit comprising:

a driving shank; a head rotatable about said driving shank; rollingcutters rotatably mounted on said head, said rolling cutters havingconical cutting faces, the axes of rotation of said cutterssubstantially converging at the axis of the bit, the rear faces of saidrolling cutters forming bearing surfaces; and gear means connecting saiddriving shank with said rear faces of sald cutting rollers, thereby totransmit directly vertical load and drilling torque from said drivingshank to said cutting rollers.

19. A rolling cutter'for a rotary well drilling bit, said cutter havinga frusto-conical crushing surface with cutting projections and anapproximately frusto-conical driving surface, the apices of such frustocones being on opposite ends of the cutter, the frustoconifial drivingsurface having recessed gear teet 20. A rolling cutter for a welldrilling bit, said cutter having a frusto-oonical cutting surface withcutting projections, a frustoconical drive surface integral with thecrushing surface, and having its apex at the opposite end of the cutter,the generating line of the crushing surface being parallel to thegeneratingline of the driving surface on opposite sides in any sectionthrough the axis of the cutter.

21. In a drill: a substantially conical roller having longitudinalcutting teeth and separate driving teeth; and drive means on said drillmeshing with said driving teeth.

22. In a rotary bit of the character described, the combination of: ahead; an inclined cutter pivoted on said head, said outter having anaxis intersecting the axis of rotation of said bit; and means rotatableaxially of said bit and engaging said cutter to take up non-axial thrustupon said cutter.

23. In a rotary bit of the character described, the combination of: ahead; a cutter pivoted on said head, said cutter having cutting teethand separate driving teeth; and means engagin said drivin teeth adaptedto synchronize t e rotation 0 said cutter and take up non-axial thrustthereon.

24:. In a rotary bit of the character described, the combination of: ahead; a plurality of cutters pivoted on said head; said cutters havingcutting teeth and separate driving teeth; and means bridgin said drivingteeth adapted to synchronize t e rotation of said cutters and take upnon-axial thrust imgosed thereon.

igned at Los Angeles, Calif, this 14th day of May, 1928.

ALFRED F. POWELL.

